1. Field of the Invention
The present invention relates to a cassette storage case preferable for storage of a tape cassette, such as audio compact cassette, and more particularly to a slide-type cassette storage case in which a cassette to be stored is inserted laterally from an insertion port provided on a side of the cassette storage case and stored therein.
2. Description of the Related Art
A compact cassette for use in audio equipment or the like is stored in a cassette storage case made of plastic or the like when it is not used.
Although various types of the conventional cassette storage cases have been developed, the inventor of the present invention has proposed a new cassette storage case as disclosed in Japanese Patent Application No. HEI10-139087.
This cassette storage case is a slide-type cassette storage case in which a cassette is inserted laterally through an insertion port provided on one side thereof and stored therein.
This conventional slide-type cassette storage case will be described with reference to FIGS. 9-11.
In FIGS. 9-11, reference numeral 11 shows a cassette storage case and an audio compact cassette 1 (hereinafter, referred to simply as a cassette) is inserted laterally into the cassette storage case 11 through an insertion port 14 provided on one side thereof and stored therein.
First, a structure of the cassette 1 is described briefly. a case 2 of the cassette 1 has a thin casing structure in which a reel driving shaft insertion hole 3 is formed on each of the right and left sides. A pair of tape reels 5 corresponding to the reel driving shaft insertion holes 3 for winding a magnetic tape 4 are rotatably accommodated within the cassette case 2.
An opening portion 6 through which the magnetic tape 4 is exposed is formed in a front portion of the cassette case 2. Within the cassette case 2, a tape travelling path is formed such that the magnetic tape 4 from one side of the tape reel 5 (supply side reel) is wound up by the other side of the tape reel 5 (windup side reel) as the magnetic tape 4 passes through the opening portion 6.
A magnetic head and the like are inserted into the opening portion 6 from a cassette deck side. To cope with the thickness of the insertion portion of the magnetic head and the like, trapezoidal expanded portions 7, which are expanded from both upper and lower surface sides, are formed at the front portion of the cassette case 2.
Further, capstan shaft insertion holes 8 and positioning reference holes 9 are formed symmetrically on the right and left sides of the expanded portions 7.
The cassette storage case 11 into which the cassette 1 is to be inserted is comprised of a upper half 12 and a lower half 13 that are joined together. The upper half 12 is plastic molding product molded from, for example, GPPS (general purpose polystyrene) material, and the lower half 13 is plastic molding product molded from, for example, HIPS (impact-resistant polystyrene) material. The upper half 12 and the lower half 13 are joined together by means of ultrasonic waves and the like.
Then, the insertion port 14 is provided on one side surface of the cassette storage case 11. The cassette 1 is inserted laterally (in the longitudinal direction of the cassette case 2) through the insertion port 14 and stored therein.
The cassette storage case 11 is so constructed as to accommodate the cassette 1 almost without any clearance. Thus, the inside the cassette storage case 11 includes concave grooves 15, 16 for accommodating the expanded portions 7 of the cassette 1 are formed on inner surface sides of the upper half 12 and lower half 13 in the lateral direction (cassette insertion direction).
Further, an opening portion 17 of an oblong-shape in the cassette insertion direction is formed in a central portion of the upper half 12 of the cassette storage case 11. When the cassette 1 is to be taken out from the cassette storage case 11, a finger (for example, thumb) is inserted through the opening portion 17 to push the cassette 1 out of the insertion port 14.
Inside the cassette storage case 11, a stopper piece 18 is provided to prevent the cassette 1 from unexpectedly jumping out of such a cassette storage state. The stopper piece 18 is formed integrally with the lower half 13 and includes an engaging protrusion 18a provided at a tip portion thereof. When the cassette 1 is stored in the cassette storage case 11, the engaging protrusion 18a of the stopper piece 18 engages with an error erase preventing detection hole (not shown) provided in the back of the cassette case 2. As a result, the cassette 1 is held in a lightly locked state in the cassette storage case 11, thereby preventing the cassette 1 from unexpectedly jumping out (slipping out) of the cassette storage case 1.
Further, a reel stopper member 19 is provided inside the cassette storage case 11 to prevent an unnecessary rotation of the tape reels 5 in the cassette 1, thereby preventing the magnetic tape 4 from becoming loose.
The reel stopper member 19 is a molded plastic product molded from, for example, polypropylene (PP) material, in which reel stopper portions 19b corresponding to reel driving shaft insertion holes 3 of the cassette 1 are formed on a base plate portion 19a thereof. Then, the base plate portion 19a is crimped to form crimping protrusions 20 provided substantially in a center portion of the inner surface of the lower half 13.
Then, when the cassette 1 is inserted into the cassette storage case 11, the reel stopper portions 19b are subjected to elastic deformation so that they are pushed down by the cassette 1. When the cassette 1 is completely accommodated in the cassette storage case 11, the reel stopper portions 19b are elastically return to an erect state because the reel driving shaft insertion holes 3 of the cassette 1 correspond to the reel stopper pieces 19b. As a result, the reel stopper portions 19b engage with the engaging protrusions 5a on an inner circumference of the tape reel 5, thereby blocking the rotation of the tape reel 5.
As described above, the conventional cassette storage case 11 is comprised of three parts including the upper half 12, the lower half 13 and the reel stopper member 19. As for the assembly procedure, first, the reel stopper member 19 is crimped to the lower half 13 and after that, the upper half 12 and the lower half 13 are fused together by ultrasonic waves.
Because the conventional cassette storage case 11 requires a complicated assembly process, production efficiency is low, which results in higher production cost.
When fusing the upper half 12 and the lower half 13 together with ultrasonic waves, a warp occurs due to uneven thickness of the upper half or lower half, so that the fusion between the upper half and lower half is not uniform. Consequently, there occurs a difference of step in the fused state or protrusion of the fusion, thereby a number of defective products being produced and production efficiency largely dropping.
Because the slide-type cassette storage case 11 has such a structure, when the cassette 1 is stored, a protrusion 10 on a side surface portion 2a of the cassette 1 comes into contact with a deep wall portion 12d of the upper half 12, as shown in FIG. 7. When stored, there is a large gap between the side surface portion 2a of the cassette 1 and the deep wall portion 12d. As a result, the cassette 1 is loose in the case so that a stabilized storage state cannot be achieved.
Further, the cassette storage case 11 has to be formed in a size large enough for completely accommodating the cassette 1. In the above described structure in which the protrusion 10 of the cassette 1 comes into contact with the deep wall portion 12d, the length in the cassette insertion direction needs to be increased by a length of the protrusion 10. Thus, the size of the cassette storage case increases and more molding material is used, thereby leading to an increase of production cost. The problem becomes large in the case where the deep wall portion is to be formed by superposing the upper half on the lower half, as shown in FIG. 7.
Further, the cassette storage case 11 is formed of resin material, such as polypropylene as described above. However, one problem that is characteristic of resin is warp or surface sink (deformation in a concave state) that is generated due to contraction after molding (particularly polypropylene is contracted largely after molding because of crystalline resin so that an excessive warp or surface sink may be generated).
Such a warp or surface sink is likely to be generated in a portion having a large difference of thickness in the completed product. That is, because in the conventional cassette storage case described above, there is a large difference in the thickness between the concave groove that retreats from the expanded portion of the cassette and the thick portion along the concave groove. The warp or surface sink is often generated at this portion after molding, so that the quality of a completed case is largely impaired.
The present invention is implemented with an object to solve these problems in the slide-type cassette storage case in which a cassette is laterally inserted from an inserting port provided on one side surface thereof and stored therein. Specifically, the objects for a new cassette storage case are as follows:
1) To provide a structure whereby the case can be downsized.
2) To eliminate the generation of warp and surface sink due to molding to improve dimensional precision.
3) To eliminate the looseness of the stored cassette.
4) To provide a cassette storage case capable of being surely and easily assembled as well as to improve production efficiency.
To achieve these and other objects, the present invention provides:
1) A cassette storage case that includes a notch formed in the deep wall portion that accommodates the protrusion provided on the side surface portion of the cassette. Because the protrusion of the cassette is accommodated in the notch in the deep wall portion when the cassette is stored, the cassette is stored in a stabilized state without any looseness.
In addition, the size of the cassette storage case can be reduced because the length of the cassette storage case in the cassette insertion direction can be reduced by a length corresponding to the protrusion, as compared to the conventional storage cases.
2) A cassette storage case having concave grooves including thickness-missing portions provided substantially in the center of the thick portion along the concave grooves.
In the cassette storage case of the present invention having such a structure, the difference of the thickness between the concave groove which retreats from the expanded portion of the cassette and the thick portion along the concave groove can be decreased, so that the generation of the warp or surface sink at this portion can be effectively suppressed.
3) In a cassette storage case having a structure in which a tape cassette is inserted laterally through an insertion port provided on a side surface thereof and stored and having concave grooves which retreat from an expanded portion of the tape cassette formed in a cassette insertion direction of an inner surface of the case, front and rear end portions in the cassette inserting direction along said concave groove are formed thick while the other portions thereof are formed as thickness-missing portions and said thick portions are defined as cassette holding portions.
In the cassette storage case of the present invention having such a structure, it is possible to surely hold the tape cassette in a state in which the tape cassette is stored at a predetermined position as well as to suppress the generation of the above mentioned warp and surface sink.
4) The present invention provides a cassette storage case comprised of a upper half and a lower half and in which a tape cassette is inserted laterally through an insertion port provided on a side surface thereof and stored, characterized in that the cassette storage case is molded integrally such that the upper half and the lower half are linked to each other in a developed state thereof and by bending a link portion between the upper half and the lower half as a hinge at the time of assembly, the upper half and the lower half are joined to each other and that reel stopper pieces elastically deformable so as to engage with tape reels in the tape cassette to block a rotation thereof are formed integrally with an inner surface of the lower half.
In this case, the upper half and the lower half are fixed to each other by engagement.
Further, preferably, polypropylene resin is used as a molding material.
The cassette storage case of the present invention having such a structure can be assembled easily without generating a deviation or a difference of step between the upper half and the lower half at the time of assembly, thereby improving production efficiency and making it possible to reduce production cost.
Further, by using polypropylene resin as molding material of the cassette storage case, its impact resistance and heat resistance can be increased.